Diesel engine fuel injector



Sept. 18, 1945. s UNSWORTH 2,385,239

DIESEL ENGINE FUEL INJECTOR Filed Feb. 8, 1945 3 Sheets-Sheet 1 Samuel A l/mswarffi f; Wm

I and/6 /1 WWW sep 18, 9 5 S.-A. UNSWQRTH 2.385239 DIESEL ENGINE FUEL INJECTOR Filed Feb. 8, 1943 5 Sheets-Sheet 2 H lawn/or 24 2f Samuel/9. Uzwrmrih W 2 mm a 9 3 m I d .f l a, w 2 w v 3 7 1 u. M Mfl A W Z d W m .J\(\\. m M. v s

3 J m 4 z, z //f Filed Feb. 8, 1943 s A UNSWORTH DIESEL ENGINE FUEL INJECTOR Sept. 18, 1945;

?atenied Eept. 18,1945

uni-Tao STATES PATENT orrics- Samuel A. Unsworth, Lawrenceville. 11!. Application February 8, 1943, Serial No. 475,152

1 Claim.

The present invention relates to new and useful improvements in fuel injecting means for Diesel engines, and has" for its primary object to provide, in a manner as hereinafter set forth, a combined pump and injector unit of novel construction which is devoid of the usual gears, push rods, et cetera, and which is adapted to be installed on the cylinder head of the engine for operation by compression from the cylinder.

Another very important object of the invention is to provide a combination fuel injector and pump unit of the aforementioned character which embodies unique control means.

Other objects of the invention are to provide a Diesel engine fuel. injector and pump combination of the character described which will be comparatively simple in construction, strong, durable, highly efilcient and reliable in use, compact, and which may be manufactured and installed at low cost.

All of the foregoing and still further objects and advantages of the invention will become apparent from a study of the following specification, taken in connection with the accompanying drawings wherein like characters of reference designate corresponding parts throughout the several views, and wherein:

Figure 1 is a view in front elevation of the device.

' Figure 2 is a vertical sectional view, taken substantially on the line 2-2 of Figure 1.

Figure 3 is a view in horizontal section, taken substantially on the line 3-3 of Figure 2.

Figure 4 is a view in horizontal section, taken substantially on the line l4 of Figure 2.

Figure 5 is a fragmentary view in vertical sectured for the passage 0! bolts 0 for securing the assembly in position on the head 2.

The body i has formed therein upper and lower cylinders 8 and i0. respectively, which are separated by a horizontal partition II. A piston I2 is mounted or reciprocation in the cylinder l0.

' Rising from the piston I2 is a rod l3 which passes tion through an intermediate portion of the device. a

Figure 6 is a detail view in elevation of the fuel compressing piston.

Figure 7 is a detail view in elevation of the lower cylinder.

Figure 8 is a top plan view of the lower cylinder.

Referring now to the drawings in detail, it will be seen that the embodiment of the invention which has been illustrated comprises a cylinder i which is mounted in the head 2 of the engine cylinder 3 in communication with the combustion chamber thereof. A seat I is provided in the upper portion of the bore of the cylinder I. The upper portion of the cylinder i is also formed to provide an external'seat 5. I

A vertically elongated cast body 6 is mounted on the seat 5. The body 6 comprises an outturned flange l on its lower end which is aperslidably through a stufling box It in the partition ll into the upper cylinder 9. A piston IE on the upper end portion of the rod i8 is operable in the cylinder 9. A removable screw plug it closes the cylinder 8 at its upper end. A coil spring I1 is mounted under tension between the plug it and the piston i5.

Extending upwardly in the piston i2 from the lower end thereof is a bore 18. Ports IS in the upper portion of the piston i2 establish communication between the bore I8 and the fuel compression chamber in the upper portion of the cylinder 10. A piston to is operable in the cylinder 1 and engageable with the seat 5. The piston 20 is provided with a tubular rod 2! which is threaded into the lower portion of the bore I8 of the piston iii, said tubular rod passing through an opening 22 which is provided therefor in the upper portion of the cylinder i. It will thus be seen that the pistons 20, i2 and ii are rigidly connected for operation in unison. The bore of the tubular rod 2| extends downwardly through the piston 20 and is enlarged to provide a seat 23. Avalve 24 in the piston 20 is engageable with the seat 23 for closing the tubular rod 2 i. The valve 25 is provided with ports or passages 26 which, when said valve is closed, are closed by the seat 23. The valve 24 further includes a stem 2% which extends upwardly through the bore of the tubular rod 2i into the bore l8 in the piston iii. A coil spring 21 is operatively connected to the upper end of the stem 28 for closing the valve 243.

4 An annular cushion 28 is provided on the top of the cylinder i for the piston i2.

The piston 15 has formed therein a passage 29 which is controlled by an upwardly opening, spring-seated check valve 30. A bypass 3! establishes communication between the upper and lower portions of the cylinder 9 around the piston IS. A port 32 communicates with the cylinder 9 at a point between the ends of the bypass 3i. port 32 at one end. At its other end, the pipe 33 communicates with a port 34 in the upper portion the engine cylinder 3. The port 3 is controlled by the engine piston 35 in the cylinder 3. The engine piston 35 has formed therein A pipe 33 communicates with the a port or passage 36 for communication with the port 34.

The body 6 is formed to 31 to which a fuel line 33 is connected. The fuel chamber 31 communicateswith the cylinder It, at an intermediate point, through a vertical series of ports 33. The body 3 has formed therein a vertical bore 40, the lower portion of which intersects the ports 33. Operable in the bore 40 is a gate valve 4| inthe form of a rod which controls the. ports 39. A bell crank lever 42 is pivotally mounted on a suitable support 43 on the upper end of the body 6. A control rod 44 is pivotally connected to one end portion of the lever 42. The other end of the lever 42 is operatively connected by links 45 to the fuel control valve 4|.

The fuel chamber 31 also communicates with the cylinder "I, at a point'above the ports 33,

through an angular intake passage 46. A suction-opened, spring-seated check valve 41 controls the fuel intake passage 43. The passage 46 is further provided with a bleeder valve 48.

Briefly, the operation of the device is substantially as follows:

With the control valve 4| in lowered or closed position, fuel is drawn from the chamber 31 through the intake passage 48 past the valve 41 into the upper portion of the cylinder III by the piston I2 when said piston l2 and the pistons l and 20 move downwardly. With the pistons |5, |2 and 20 in lowered position, the engine piston 35 moves upwardly on its compression stroke in the engine cylinder 3. In this manner a balanced pressure is created beneath the piston 20. and above the piston |5 through the port 34', the pipe 33 andthe port 32. This balanced pressure is built up until the engine piston 35 closes the port 34. Th engine piston 35 continuesto move upwardly and the pressure is increased beneath the piston 20. When the port in the cylinder 9 above the piston is released. This sudden unbalancing of the pressure above and below the assembly causes the pistons 20, I5

inders, the latter compressing the fuel in the upper portion ofits cylinder M. This compressed fuel rushes through the ports l9 into the bore l8 and opens the valve 24 against the tension of the spring 21. When the valve 24 is thus opened, the fuel passes through the ports 25 into the firing chamber of the engine cylinder 3. This injection operation ceases when the piston engages the seat 4 and is arrested thereby. The assembly is held in raised position during the firingv stroke of the engine by the pressure in the cylinder 3. The piston I5, when in raised position, as seen in Figure 2.0f the drawings, closes the, port 32 for'preventing pressure from entering the cylinder 9 during the power stroke of the engine. The bypass 3| prevents air or gas from being trapped in the cylinder 9 above and below the piston l5 and also prevents the creationof a. vacuum in said cylinder. When the piston I5 is in lowered position, itcloses the bypass 3| at its lower end. The check valve 30 prevents the trapping of air or gas below the provide a chamber 36 communicates with" the port 34, the pressure cylinder l0. when the control valve 4| piston I! when the bypass 3| is thus closed. of course, the coil spring I"! yieldingly urges the assembly downwardly. When the fuel injection operation ceases, the valve 24 is closed by its spring 21. The lowermost port 33 is just above the piston I2 when it is down, and the uppermost port 33 is just above said piston when it is up. When the piston l2 moves upwardly on its compression stroke and with the control valve 4| in fully closed position, all of the ports 33 are closed andnone of the fuel which has been previously drawn into the upper portion of the cylinder -|fl through the passage 0 can escape back to the chamber 31 through said ports. Thus, the maximum fuel charge will be compressed in the upper portion of the is raised, the ports 39, beginning with the lowermost thereof, are successively opened for permitting the desired portion of the fuel in the cylinder M to return to the chamber 31 when the piston l2 moves upwardly. In this manner the volume of fuel injected into the engine cylinder may be controlled or regulated as desired.

'With the control valve 4| in fully open position,

all of the ports 39 will be open and consequently substantially all of the fuel in the cylinder |3 will be returned to the chamber .31.

, vention as claimed.

and I? to move upwardly in their respective cyli What is claimed is:

o In combination with a Diesel engine comprisins a cylinder having a port therein near the top thereof and a piston operable in the cylinder and controlling the port, said piston having a vent port therein near the top thereof for communication with the first-named port, upper, lower and intermediate cylinders mounted on the engine, said lower cylinder communicating with the top of the engine cylinder for receiving pressure therefrom, pistons operable in the upper, lower and intermediate cylinders,

- the second-named pistons being connected for operation in unison, the pistonwin the lower cylinder being operable by pressure from the engine cylinder, a conduit connecting the firstnamed port to the upper cylinder for conducting pressure thereto above the piston therein when the latter is lowered, the latter piston, when raised, acting to out off communication of its cylinder with said conduit, the piston in the intermediate cylinder constituting means for drawing fuel thereinto and compressing said fuel, means to prevent creation of a partial vacuum and pressure, respectively, on opposite sides of the piston in the upper cylinder when said piston is moved, and valve controlled means for conducting the compressed fuel into the ,engine cylinder.

. SAMUEL A. UNSWORTH. 

